8-甲氧补骨脂素诱导的四膜虫DNA损伤修复

Repair of 8-methoxypsoralen induced DNA damage in Tetrahymena thermophila

用0.6 μg·ml^(-1)8-甲氧补骨脂素(8-methoxypsoralen,8-MOP)与365 nm UVA(紫外线)联合处理后,四膜虫DNA的修复反应,表现为细胞增殖反应受抑;DNA,RNA合成率在0 h受抑,(DNA为对照的5％,RNA为对照的20％),但经过一段修复后,DNA,RNA合成率均回升,在24h,DNA达70％,而RNA则几乎100％,同样条什下,用分子杂交等技术,观察到在0 h产生了分子交联(DNA双链在受热100℃时仍不能解链),经过24h培养后,有部分分子交联被去除(受热后DNA解链且被S1酶降解)。

The protozoan Tetrahymenathermophila was treated with 0.6 μg·ml-1 of 8-methoxypsoralen in combination with long wavelength ultraviolet irradiation and the DNA repair response was studied. Following the treatment, an inhibition of cell proliferation was observed. The treatment resulted in a 95% and 80% decrease in the rates of DNA and RNA synthesis at the zero time, respectively, but after 24 h following the treatment, they were recovered in varying degrees (DNA 70%, RNA 99.8%). Using the same conditions, during 24 h repair period, the majority of psoralen induced DNA interstrand crosslinks were removed.